San Diego, California
, is the home of this year’s Infectious Disease Week conference, a conference where healthcare investigators from all over the world can come together to share recent research that could help the field get a leg-up on infectious diseases. Unfortunately, it is also the home to a severe ongoing hepatitis A outbreak
that has infected a staggering 481 individuals thus far, leaving health officials scrambling.
In light of the outbreak, Monique Foster, MD, MPH, from the Division of Viral Hepatitis in the Centers for Disease Control and Prevention, and Eric McDonald, MD, MPH, from the Epidemiology and Immunization Services Branch of the San Diego County Health and Human Services Agency, discussed the “surprising return” of the virus as part of the “Late Breakers I” symposium at the conference.
“To really understand hepatitis A virus outbreaks
, it’s important to understand the global patterns of transmission,” Dr. Foster explained. In the United States, endemicity is very low and outbreaks are uncommon; in fact, hepatitis A infection is typically seen in travelers who have visited endemic regions. However, she added, “When outbreaks do occur, they can be large and prolonged.”
The hepatitis A vaccine
was first introduced in 1995, according to the CDC, and healthcare professionals routinely vaccinate all children, travelers to certain countries, and persons considered at-risk for infection. “Since the introduction of the hepatitis A vaccine, reported cases of hepatitis A infection have decreased by 95%,” Dr. Foster shared. Incidence has decreased in all age groups; however, the highest rates of infection are now found in adults, whereas before vaccine introduction, most outbreaks involved asymptomatic children. As individuals grow older, not only are they more likely to be symptomatic, but the severity of the disease and their likelihood of experiencing adverse consequences are increased. Perhaps even more unsettling is that there are no universal vaccination recommendations for adults, and vaccination uptake among at-risk adults, who do have existing vaccination recommendations, remains low.
The 5 largest hepatitis A virus outbreaks in the United States, in the post-vaccine era, have occurred within the last 5 years, with over 1400 outbreak cases having been reported to the CDC within just the last 15 months. “And just to put this into perspective,” Dr. Foster stated, “only 459 outbreak cases were reported in the 10 years between 2005 and 2015,” underscoring the severity of the current situation.
“Another distinctive aspect about the recent hepatitis A outbreaks from the past year is that there was a shift to hepatitis A genotype 1B,” Dr. Foster shared. She added that most of the outbreaks that have occurred within the last 5 years have been associated with genotype 1B, including the current outbreak in San Diego.
To this end, Dr. McDonald took the audience on a journey from the beginning of the San Diego hepatitis A outbreak investigation up to current efforts being made to quell it. This outbreak started in early March 2017, when an increase in the number of hepatitis A cases was noted to be above baseline. “From November 2016 through February 2017, between 7 and 9 cases were expected, and 19 cases were reported,” he shared.
The San Diego County Health and Human Services investigation approach included the following:
- The administration of a standard hepatitis A questionnaire addressing potential exposure sources (food, drink, close contact)
- A supplemental questionnaire that looked at drug use, homeless service access, hygiene practice, and restroom use
- Identification of cases with sensitive occupations (such as food handlers or health care workers)
- Investigating possible sources of the outbreak (food, water, drugs) in conjunction with environmental health workers
- Arrangements to send specimens to the CDC’s Viral Hepatitis branch to confirm presence of hepatitis A virus RNA
“From 2009 to 2016, there were just [24 to 36] cases per year,” Dr. McDonald reported, most likely due to the introduction of the hepatitis A vaccine. However, in 2017, there has been a rise. “As you can see in 2017, we are now at just under 500 cases reported so far.”
He confirmed that as of Monday, October 2, 2017, there have been 481 confirmed and probable cases associated with the ongoing outbreak as well as 17 deaths; 70% of those infected required hospitalization. Those infected range in age from 5 years old to 87; however, the 5-year-old is the only pediatric case in this outbreak. A total of 33% of those infected are homeless and illicit drug users, 17% are homeless only, and 12% are illicit drug users only. “Most of the cases live in group homes or single room occupancy hotels or jail and have shared restroom facilities with 1 of those 2 at-risk groups,” he added.
The majority of the cases in the outbreak are genotype 1B. In addition, several of the infected individuals are suffering from a coinfection, with 17.5% of cases coinfected with hepatitis C and 5.8% of the cases coinfected with hepatitis B. Unfortunately, despite “exhaustive investigation” a common source of the outbreak has yet to be identified.
Healthcare officials remain vigilant in their efforts to quell the outbreak. Some of these efforts include:
- The development of an Incident Command System to manage the outbreak
- Conducting case investigations
- Providing post-exposure prophylaxis
- Ongoing communication with the United States Department of Housing and Urban Development to schedule a technical assistance visit to look at housing and sanitation for individuals
- Issuing a local health emergency on September 1, 2017
The overall strategy to tackle this outbreak has involved vaccinating individuals who are at risk of infection, promoting proper sanitation and hygiene, and providing education for prevention.
“Hepatitis A is a routine childhood vaccination and children are well-immunized in San Diego. However, like most of the country, and as Dr. Foster mentioned, we have lots of room for improvement in adults, particularly in travelers, men who have sex with men, illicit drug users, and people with chronic liver conditions,” Dr. McDonald stressed. A total of 45% of hepatitis A cases are illicit drug users and none had been previously immunized, indicating “major missed opportunities for prevention.” Local recommendations that have been raised to fix the problem have been: vaccinating homeless, vaccinating those in close contact with the homeless population, and janitorial as well as sanitation workers.
In addition to these recommendations, efforts are being made on a street level, including mass vaccination events where healthcare workers took to the streets to make the vaccine available to at-risk individuals. The efforts seem to be working—54,073 vaccinations have been issued since the outbreak was identified.
Efforts have also been made to improve sanitation. Over 5,000 hygiene kits were developed and distributed to educate individuals on proper hygiene practices, and disinfection guidelines have been distributed. Furthermore, 66 handwashing stations were installed in areas with high concentrations of at-risk individuals. “And we’ve actually researched and provided to local cities street sanitation protocols to better address the environmental burden of hepatitis A,” Dr. McDonald added.
The efforts do not stop there—community talks, public ad campaigns, and fact sheets have all been designed to educate the public, particularly those at-risk, on hepatitis A. “We continue to work with community stakeholders to increase vaccination efforts and awareness,” Dr. McDonald concluded. The hope is that with these efforts, health officials will be able to turn the tide in the fight against this massive hepatitis A virus outbreak and hold off future infections.
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